cgroup: pass around cgroup_subsys_state instead of cgroup in file methods

cgroup is currently in the process of transitioning to using struct
cgroup_subsys_state * as the primary handle instead of struct cgroup.
Please see the previous commit which converts the subsystem methods
for rationale.

This patch converts all cftype file operations to take @css instead of
@cgroup.  cftypes for the cgroup core files don't have their subsytem
pointer set.  These will automatically use the dummy_css added by the
previous patch and can be converted the same way.

Most subsystem conversions are straight forwards but there are some
interesting ones.

* freezer: update_if_frozen() is also converted to take @css instead
  of @cgroup for consistency.  This will make the code look simpler
  too once iterators are converted to use css.

* memory/vmpressure: mem_cgroup_from_css() needs to be exported to
  vmpressure while mem_cgroup_from_cont() can be made static.
  Updated accordingly.

* cpu: cgroup_tg() doesn't have any user left.  Removed.

* cpuacct: cgroup_ca() doesn't have any user left.  Removed.

* hugetlb: hugetlb_cgroup_form_cgroup() doesn't have any user left.
  Removed.

* net_cls: cgrp_cls_state() doesn't have any user left.  Removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index da14436c1735..8a57d79b0b16 100644
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -132,10 +132,10 @@ static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
         return 0;
 }
 
-static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft,
+static int tcp_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
                             const char *buffer)
 {
-        struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+        struct mem_cgroup *memcg = mem_cgroup_from_css(css);
         unsigned long long val;
         int ret = 0;
 
@@ -180,9 +180,9 @@ static u64 tcp_read_usage(struct mem_cgroup *memcg)
         return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE);
 }
 
-static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
+static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
 {
-        struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+        struct mem_cgroup *memcg = mem_cgroup_from_css(css);
         u64 val;
 
         switch (cft->private) {
@@ -202,13 +202,13 @@ static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
         return val;
 }
 
-static int tcp_cgroup_reset(struct cgroup *cont, unsigned int event)
+static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
 {
         struct mem_cgroup *memcg;
         struct tcp_memcontrol *tcp;
         struct cg_proto *cg_proto;
 
-        memcg = mem_cgroup_from_cont(cont);
+        memcg = mem_cgroup_from_css(css);
         cg_proto = tcp_prot.proto_cgroup(memcg);
         if (!cg_proto)
                 return 0;